Multiple stage cementing



May 21, 1940- w. D. OWSLEY ET AL.

MULTIPLE STAGE CEMENTING Filed March 21, 1958 5 I M I0 Y pwlv. file W .1 M E m m W Wk m mm A I M 1 \Mfi? 0 Q 0i we M :lv 0 B a. a w m w m 2 3 a m m w A 1 .5 I II ll. i1

Patented May 21, 1940 UNITED STATES PATENT OFFICE MULTIPLE STAGE OEMENTING William D. Owsley and Robert L. Shook, Duncan,

Okla", assignors to Halliburton Oil Well Cementing Company, Duncan, Okla.

This invention relates to the cementing of oil wells or the like and more particularly to an arrangement for cementing long strings of casing or pipe in stages so that all of the cement which fills the annular space around the casing may be supplied thereto without passing around the bottom of the casing.

The multiple stage cementing of wells is now well known to those skilled in the art. A method and apparatus for accomplishing this is fully disclosed in the United States patent to Halliburton, No. 1,860,669, granted May 31, 1932, and in the reissue thereof, No. 19,570 reissued May 14, 1935.

In the multiple stage cementing of wells a valve structure, usually called a. multiple stage unit, is made up with the casing. The arrangement is such that at the proper time the valve in thisunit is opened so that cement can flow outwardly therethrough to the annular space surrounding the casing. The valve may be a sleeve valve, as taught in the patents mentioned above, and may be opened by one of the cementing plugs used in the multiple stage cementing operation.

As taught in the above-mentioned patents, a multiple stage cementing operation may employ several plugs. Thus, for example, in the illustration of Figures 9 and of the reissued Patent No. 19,570, two plugs travel through the multiple stage unit without affecting it, a third plug enters the multiple stage unit and opens the valve and a fourth plug follows the upper body of cement which flows out through the multiple stage unit.

After the cement has passed through the multiple stage unit, some means should be provided for preventing that cement from flowing back into the casing. The reissued Patent No. 19,570 discloses spring-pressed valves 37 on the multiple stage unit for this purpose.

It is an object of the present invention to devise a novel multiple stage unit which has certain advantages in construction and operation over the previous apparatus for this purpose.

It is a further object of the invention to devise a multiple stage unit with valves which do not project outwardly beyond the outside of the casing and which are sure to properly close after the cement has passed outwardly through the unit.

f It is still another object of the invention to devise a multiple stage unit with an inner sleeve valve which is made of drillable material so that after the cementing operation has been completed this inner sleeve may be removed and leave the inside of the casing smooth and free from ob- 55 struction.

Other objects and advantages reside in certain novel features of the arrangement and construction of parts as will become more apparent from a consideration of the following description taken in connection with the accompanying drawing, in which;

Figure 1 is a view in side elevation and in quarter section of a specially prepared collar adaptecl'to be made up with the casing to be lowered into an oil well, this collar constituting the main body of the multiple stage cementing unit constructed in accordance with the present invention;

Figure 2 is a view in side elevation and in. quarter section of the inner drillable sleeve adapted to be fitted into the collar shown in Figure 1 in accordance with the invention;

Figure 3 is a view in side elevation and in quarter section of the cementing plug which is adapted to cooperate with the sleeve shown in Figure 2 to move the same at the proper time during the cementing operation;

Figure 4 is a view in side elevation of several parts of the multiple stage unit which cooperate to make up the external valve thereof and several of which are mounted upon the collar shown in Figure 1; r

Figure 5 is a view in vertical cross-section showing the parts shown in Figures 2 and 4 assembled with the collar shown in Figure 1;

Figure 6 is atransverse quarter section of the assembly shown in Figure 5; and

Figure 7 is a view in vertical quarter section of the arrangement shown in Figure 5 and also showing the plug shown in Figure 3 seated therein with the parts in the position which they take during the flow of cement outwardly through the assembly.

From what has been said above, it will be apparent that the apparatus which constitutes the subject matter of the present invention is to be made up with the casing to be lowered into the well for use in the multiple stage cementing thereof. Since the multiple stage method of cementing is well known, it need not be described herein in detail and the apparatus shown in the drawing does not include the casing, it being understood that the arrangement shown and described herein may be used in place of the similar apparatus shown in the Halliburton Reissue Patent No. 19,570 in Figures 9 and 10, at 8, 33, 35, 36, 3'7, 38, 40, 41 and 42.

Referring to the drawing in detail, it will be seen that the main portion of the multiple stage cementing unit consists of a collar designated Ill generally at II which collar constitutes the main member of the multiple stage cementing unit and is internally threaded at its upper and lower ends as shown at l2 and I3 so as to be made up with casing. The collar II is provided with a number (in the present arrangement four are provided) of longitudinally extending flutes'or recesses ll. Near the upper ends of these flutes ports or passageways l5 are made in the collar I I, these ports being slightly less in circumferential dimension than the width of the flutes. The ports constitute openings through which cement or other fluid may be passed outwardly during the cementing operation. When the apparatus is assembled with the casing these ports ii are closed both internally and externally by suitable movable valve deviceswhich thus cooperate with the ports to constitute a double seal. To eflect the inner seal, the sleeve member l6 shown in Figure 2 is provided, this sleeve being of substantially the same external diameter as the internal diameter of the collar ll so as to have a tight flt therewith. The sleeve I5 is provided with a conical seat I! at its lower end adapted to receive and form a tight seal with the similar seat l8 on the cementing plug l9 shown in Figure 3. In assembling the unit the sleeve I6 is placed within the collar Ii as shown in Figure 5 and is secured thereto by means of a pin made of shearable material, this pin fltting into corresponding holes 2| and 22 in the sleeve and collar respectively.

After securing the internal sleeve as mentioned above, external gate valve assemblies are mounted. upon the collar II. There being four ports l5 in the collar II in the arrangement shown, four separate external gate valve assemblies are provided. One of these assemblies is shown in Figure 4 and consists oi aslideable valve member 23, two or more small coil compression springs designated 24, an upper guide member and a lower guide member 26. The valve member 23 consists essentially of a segment of acylinder with parallel sides provided with a segment of a ring on its external or convex surface as shown at 21. The ring segment 21 has a tapered upper surface as shown at 28 which is adapted to cooperate with a similarly tapered surface 29 on the lower edge of the guide member 25. The

guide members 25 and 28 are also segments of ,a cylinder but are of slightly greater width than the valve member 25, as is best shown in Figure 6.

The collar H, in addition to the flutes I4, is provided with upper recesses and lower recesses 3| adapted toreceive the guide members 25 and 26 so that after these and the sliding valve members 23 are assembled all are flush with the greater diameter of the collar II as shown in Figure 5, it being noted that the segment of a ring 21 on the valve members 23 arealso flush with the guide members 25 and 26. As shown in Figure 5, the coil springs 24 are placed within the flutes ll beneath the valve members .23 so as to urge these upwardly at all times. The guide members 25 and 26 are assembled on the outside of the valve members 23 and are then welded in place.

As best shown in Figure 5, when the parts are thus assembled each port 15 in the collar II is effectively sealed off not only by the internal sleeve it but also by the seating of the ring segment 21 against the lower edge of the upper guide segment 25. The sleeve It, as long as it covers the ports l5, will prevent any fluid flowing outwardly through the ports l5 and the valve members 23, whenever they are held up against the guide segments 25, will prevent fluid flowing into the collar ll through the ports i5.

After the assembly 'Just described has been made up with the casing and lowered into the well, the cementing operation may proceed in the usual manner. When it is desired to open the ports IS the plug l8 shown-in Figure 3 is placed in the well and when it moves downwardly into contact with the seat ll in the sleeve l8 and pump pressure is exerted thereon, the pins 20 will be sheared and the parts will take the position shown in Figure 'l. Fluid will then flow outwardly through the ports i5 and under the pressure of this fluid the valve segments 23 will move downwardly unseating the ring segments 21 from the guide segments 25 so that cement orother fluid can flow outwardly through the assembly. As soon as the pump pressure is relieved the springs 24 will push the valve segments 28 upwardly and again effect a seal between the ring segments 21 and the guide segments 25.

The advantages in the arrangement just described over those previously used in multiple stage cementing operations are several. Where valves of the type shown in the Halliburton Reissue Patent No. 19,570 are employed it some- .times happens that they do not effectively close.

Sometimes this is due to the fact that as the fluid flows outwardly the valve seats are cut away by sand or other abrasive material in the'fluid and sometimes due to the fact that they are forced outwardly against the wall of the hole where they become stuck or bent. It is also of advantagein accordance with the present arrangement to have a multiple stage unit which does not have anything projecting exteriorly of the normal diameter of the collar so that there is no danger of a valve being pulled off or bent as the unit is being lowered into the well. Still a further advantage results from the fact that the sleeve I6 is made of aluminum or other drillable material. After the cementing operation is completed the plug i9 and the sleeve It may cal member adapted to be made up with the casing and having ports therein, and longitudinally extending flutes on the outside thereof, there being one flute for each port, a sleeve mounted within said member and adapted when in one position to cover the ports therein to prevent outward flow of fluid therethrough, gate valves mounted for longitudinal sliding movement on i the outside of said member and adapted when closed to prevent the passage of fluid into said valves mounted on the outside 01' said members in said flutes and adapted when closed to prevent flow of fluid through said ports, and spring means cooperating with said gate valves to urge the same into closed position.

3. Apparatus for use in the multiple stage cementing of casing in wells including a cylindrical member adapted to be made up with the casing and having ports therein, said member having an internal diameter equal to that of the casing with which it is to be used, a sleeve of drillable material mounted within said member and a shear pin for holding said sleeve in position to cover said ports, the arrangement being such that after the cementing operation, the sleeve may be drilled up and removed from the well leaving the interior of said member free from obstruction and of the same diameter as the 

